What flux is best for soldering boards. Choosing a flux for soldering. Description of refractory fluxes for soldering

Soldering is widely used today in various industries, it is used to obtain a permanent connection between solid materials. However, in order for the work to be done efficiently, you need to have the necessary set of tools and equipment, as well as consumables.

Flux is one of those materials. And today we will talk about what it is and what this subject represents.

What is flux and its key features

So, flux is such an alloy of metals that has a fusible structure, which is used for soldering two different materials. This alloy can be made with your own hands, if you know the features of joining two different materials during their heat treatment.

The connection of two materials with the help of a flux comes out, provided that one or another temperature is maintained at the level of the seam. Depending on what material is taken, temperature varies from 50 to 500 degrees. The melt temperature of the solder must be much higher than the melt temperature of the material you are processing.

Such a thing as soldering flux has several varieties, it must be chosen depending on such factors:

• metal;
• soldering temperature.
• the temperature of the flux itself;
• work surface parameters;
• material strength;
• its resistance to corrosion.

There are two groups of fluxes:

• solid, which have a high temperature threshold;
• soft, such a flux has a low melting point.

Refractory solder has a melting temperature of 500 degrees or more, it creates a fairly strong type of connection. But its disadvantage is that sometimes a high temperature can cause a key part of the structure to overheat and disable it.

And the melting temperature of low-melting solders is from 50 to 400 degrees. This type of flux includes the following components:

• lead;
• tin;
• other impurities.

Such fluxes are mainly used for soldering radio engineering items during their installation.

There are also ultra-low-melting solders, which are used for soldering and connecting transistors. The melting temperature of these fluxes can reach 150 degrees maximum.

To solder thin surfaces, soft fluxes should be used, and for soldering wires with a large diameter, hard solder should be taken, which has a high temperature threshold.

The required characteristics of the flux are:

• the ability to conduct heat and current normally;
• structural strength;
• stretching ability;
• resistance to corrosion;
• differences in temperature indicators during the melting of solder and base materials.

In the form of solder, materials such as:

• rods;
• tapes;
• wire coils;
• tubules with colophony;
• other flux.

The most common form is a tin rod with a cross-sectional diameter of 1-5 meters.

There are also multichannel types of fluxes that have multiple sources of solder to create stronger joints. They are can be sold in skeins or flasks, have a spiral shape and be contained in reels. For a one-time use, it is best to take a small piece of wire the size of a match.

For soldering electrical circuits, it is necessary to use tube fluxes that contain colophonium. This is a resin that plays the role of solder. This filler material is perfectly capable of joining such types of metals as:

• copper;
• silver;
• brass.

Features of fusible fluxes for soldering

Fluxes for soft soldering are capable of melting at temperatures up to 400 degrees. With their help, the seam becomes strong, soft and elastic.

Low-melting fluxes are divided into the following categories:

The best option for solder is tin, but in its pure form it is practically not used, since this material is too expensive in itself. The most commonly used solders are tin-lead, which give strong connections.

The marking of such a flux contains the percentage of tin contained in it. Also, such solders contain antimony in a small amount and can be used for non-critical types of joints that are not subject to stress or vibration.

Lead-free low tin flux is used for soldering contacts on small electrical circuits at temperatures up to 300 degrees.

At temperatures from 60 to 145 degrees, ultra-low-melting fluxes able to go into a liquid state and be used for manual soldering of delicate parts. The connection is not very strong.

And special solders are needed when it is necessary to obtain compatibility of characteristics with the main type of material. For this, compositions that cannot be soldered are taken, including:

• aluminum;
• nickel;
• low carbon steel;
• cast iron.

So, for soldering aluminum parts, you need to make solder, which almost entirely consists of tin, and for better diffusion, you need to add zinc, borax and cadmium in a small amount to it.

Description of refractory fluxes for soldering

Hard solder is used to connect seams that are subjected to various loads, shocks, vibrations and temperature changes. These fluxes are capable of melting at temperatures from 400 degrees.

Hard solders are divided into the following categories:

• copper-zinc alloys;
• phosphorus-copper alloys;
• silver flux;
• pure copper.

It should be noted that copper-zinc alloys are not used very often, since the strength of the seam is not too high, and their cost is unreasonably high.

Such solder can be replaced with brass, or a bronze-zinc alloy.

A copper-phosphorus alloy can be used for brazing copper, bronze and brass parts that are not heavily stressed, and it is also used instead of more expensive silver solder.

Solid fluxes should not be used when brazing cast iron and mild steel, since when iron is heated with copper or phosphorus, brittle elements are formed, which then destroy the seam.

The best solder for iron is silver, but very expensive. However, with its help, the materials are connected quite firmly. Silver solder is used for soldering wires, complex silver-based circuit boards.

Classification of alternative types of solder

There are also other alternative types of solder:

• flux with increased anti-corrosion characteristics based on acids, phosphorus and solvent. After soldering, there is no need to apply additional cleaning agents;
• liquid type fluxes based on petroleum jelly, gold, salicylic acid and ethyl alcohol. They are used for soldering electrical wires or radiators, and the seams come out neat and clean;
• rosin combined with air. This flux is neutral and is used for high precision electrical appliances such as relays, switches, mobile phone circuits. Rosin should be used on pre-tinned and cleaned metals, and in order to clean diamond contacts with high quality, you can take a laser;
• borax mixed with rosin. This mixture is used for soldering water pipes made of copper, it is highly active and does not require stripping of materials. Borax is able to melt at a temperature of about 70 degrees and does not emit harmful substances;
• homemade activated flux, used for soldering connections that are often subject to shock and other loads. To prepare it, you need to mix aniline rosin, anhydride, diathylamine and salicylic acid;
• flux based on rosin with alcohol. It belongs to the active ones, but at the same time, during high temperatures, not only the oxide is removed, but also the metal itself. In addition, after soldering, you need to thoroughly clean the board.

Do not leave flux residues, they are not only unattractive, but also harmful. In electrical circuits, they can cause a short circuit if the surface is not cleaned in time.

To carry out soldering with tubes with colophonium, you need to do the following:

• clean the surfaces to be joined from oxidation and dirt thoroughly;
• the part at the seam must be heated to a value that exceeds the melting temperature of the flux;
• we make soldering.

This method should not be practiced for large surfaces with good thermal conductivity, since the power of the soldering iron will not be enough to heat the metal sufficiently.

How to assemble flux for soldering with your own hands

For the purpose of soldering radio wires, solders can be used in the form of thin rods with a diameter of 2 mm, which are easily made by hand.

To make them, you need a vessel, at the bottom of which a hole is made, and then tin-lead solder will need to be poured into it in molten form. In this case, the vessel should be located above a tin sheet or above a metal plate. After the rods have hardened, they can be cut into pieces of the required length.

This mixture can also be poured into molds:

• tin gutters;
• duralumin containers;
• plaster.

This is all done in the following way:

• weigh on the scales the right amount of lead and tin;
• melt the metal in a metal crucible over a gas burner, while stirring it with a steel rod;
• remove a thin film from the melted surface with a steel plate;
• pour the alloy into molds.

Regardless of what type of flux you use, wipe the finished solder with a cloth previously moistened with acetone or rectified. The seam is cleaned with a stiff brush, which must first be dipped in a solvent.

On the market you can buy liquid and gel no-clean fluxes which have the following advantages:

• the absence of components that provoke oxidation and corrosion;
• this type of flux does not conduct current;
• no cleaning required after soldering.

This type of liquid flux should be applied with a cotton swab or brush. You can also make devices for applying it yourself based on a conventional syringe and a silicone hose, which will be filled with liquid flux.

Soldering is one of the best methods for joining metals. She provides high level of strength, tightness, the process itself is simple and does not take much time compared to welding.

However, soldering is harmful because harmful gases are released during it, so you should not forget about protective gloves, glasses and an apron based on dense fabric.

In addition, the risk of poisoning can be significantly reduced by using mixtures from good manufacturers.

All the best! This rating contains the best fluxes for soldering and is compiled from personal preferences and feedback from electronics repairmen. Many readers will now think - “Well, finally! Master Soldering has started to write something about soldering!” and they will be right - for almost 4 years, not a single decent article about the soldering process has been written on the blog, although the name of the blog seems to oblige. I admit, I confess, I will correct the situation.

I plan to publish reviews of soldering processes, soldering tools, soldering videos and new technologies in the soldering world. And today I will give my rating of the 10 best fluxes for soldering. This rating is based on personal preferences and all kinds of feedback from familiar electronics repairmen of various levels and does not claim to be exclusive. Let's go - fluxes for soldering.

Rating of the most popular soldering fluxes

What should we know about flux?

The flux is designed to improve the quality of the process of soldering two metal surfaces by soldering and, when heated, cleans the surfaces from oxide and greasy films. A good flux should have a low melting point and low specific gravity. Before the solder melts, it must have time to dissolve the oxides and not penetrate deep into the solder joint during the soldering process. The flux should spread well and wet the surface of the solder and the metal at the place of soldering.

In fifth place is the most popular flux of all time, the muse of musicians, gift of nature, her majesty rosin. Rosin is gum (from the resin of coniferous trees, has almost no fatty acids), extraction (extraction of coniferous sawdust with gasoline, contains more fatty acids than gum) and tall (residues after sulfate-cellulose production of soap).

In fourth place is the beloved alcohol-rosin flux SKF or FKSp (soldering alcohol-rosin flux). It consists of 60-80% alcohol and 20-40% rosin. Such a mixture can be prepared at home with your own hands. For example, many simply crumble rosin into alcohol in a ratio of about 1 to 3. It is convenient to use in a syringe with a needle. But when stored in a loosely closed syringe, it begins to dry out on the needle and stops flowing.

Advantages:

affordable and popular inactive flux, easy to apply, does not smoke much.

Disadvantages:

when heated, the alcohol begins to rapidly evaporate and hiss.

What to solder: copper wires, gold-plated and silver-plated contacts of microcircuits and radioelements, brass, zinc.

How to rinse: alcohol, solvents, gasoline, alcohol-gasoline mixture.

So we got to the Top 3 best soldering fluxes. On the prizes, I placed professional fluxes, which in ordinary life may not be useful. But in the craft - they are very necessary.

Fluxes Amtech RMA-223 and Kingbo RMA-218

The third bronze place is occupied by Amtech RMA-223 - it is a gel flux - a mixture of crushed rosin and solvent.

I also suspect that there may be activators and fragrance in the composition. - the biggest sign of a fake- on the sticker there is an inscription in small print “Coliformia” instead of “California”, however, oddly enough, the Chinese fake flux is very good in operation, and many services just sit on it. Although the masters from mysku do not advise to take this flux for Ali, but it is better to take an analogue.

Advantages:

it is convenient to apply the gel, good solderability, you can not wash it, a fake is cheap (about 200 rubles), but it soldered very well with it and smelled of perfume.

Expensive (a 10 g tube can cost 1,500 rubles), smelly, fakes come across. The price is a limiting factor, for example, a 30 g tube can cost from 2,000 rubles.

What to solder: mainly responsible lead-free and lead soldering.

How to rinse: most can not be washed off, alcohol, solvent, there is a proprietary solvent T2005M.

This concludes the Top 10 best soldering fluxes. Of course, there are a lot of other fluxes, including good Chinese and top German and Japanese ones. But I haven't used them, so I can't adequately describe them.

If you, dear readers, use any other flux and consider it the best in the world, then be sure to write to me about it in the comments. Perhaps it will appear in the rating after testing.

Soldering Master tried for you.

Hello.

Today's review will focus on three Chinese fluxes that I purchased on eBay. I bought them after my home stock of this soldering accessory began to run low. Since I had not ordered this type of product from China before, and in general I did not use Chinese fluxes, I decided to buy several different jars at once, fortunately, they all cost mere pennies - $ 0.99 per item.

All three lots were ordered in the same store, so as not to rush to the post office 3 times. So the order was placed and paid for, and the next day the seller gave me a track to track it. So you can see all the information about moving a parcel from China to Belarus.

So, as I said, I ordered 3 different fluxes.


As a test, we will try to use them to tin and solder stranded copper wires. True, the wires are terribly oxidized. I was specifically looking for three pieces that were identical in cross section and similar in contamination.


Some kind of car connector will act as an object of soldering, which has been idle in my garage for many years. He also managed to pretty much oxidize and dust. For the purity of the experiment, neither the wires nor the connector will be cleaned before the start of the “procedure”. Actually, the connector itself to which we will try to solder the wires (to a metal arc):


But before proceeding directly to the review, let me remind you what a flux is and what it is for. Flux - substances (usually a mixture) of organic and inorganic origin, designed to remove oxides from the surface to be soldered, reduce surface tension, improve the spreading of liquid solder and / or protect against environmental influences.
First - RMA 223, ordered .

It is delivered as if in a syringe, however, this syringe has neither a piston nor a needle :) But you should not worry about it accidentally leaking out.

Description (Google translation):

Type: RMA-223.

Good dive;
Volume: 10ml / 10cc;
Size: 95 x 35 x 23 mm.
RMA-223 is a high viscosity impure flux, it can be used to recycle PCB, BGA, PGA, it can be used to solder and reball computer and phone chips. It is a mixture of high quality alloy powder and resinous paste flow, it can avoid pale yellow residue, so you can easily clean the board.

This flux has a gel-like consistency, which makes it easy to apply. Outwardly, it has a pale yellow color, in the light it is cloudy.


When heated, it spreads perfectly and smokes :) I would like to believe that it also actively penetrates between the strands of the wire.


Second - PPD PD-18, (although PD-10 is written on the jar) was ordered.

Unlike the first one, it comes in a metal jar, somewhat reminiscent of jars from Asterisk balm, although several times larger. If in the first case the syringe was airtight, then the iron jar turned out to be not such a reliable package. At the time of receipt, it was all in flux, both inside and out. Carefully wiped everything, threw it into the shelf. Got it after some time - again the same story. So you need to store it carefully, do not allow the jar to turn over, otherwise its contents may not live up to soldering - it will leak out.


Description (Google translation):

Type: PPD PD-18;
Weight: 10g;
Peculiarities:
joint high intensity;
Good dive;
Neutral PH7±3;
No poison no;
Good insulation;
Smooth welding surface;
There is no wear.

In its consistency, it is thicker than the first and has a more pronounced orange color. They smell similar, but it's hard to say exactly what they smell like. The smell is familiar, but I don't remember exactly what.

An open jar provides excellent access to the contents. If you want to dip the postings, if you want to shove the fee :)


When heated, it also spreads beautifully and smokes perfectly. There seemed to be a little more smoke than in the case of the first one and it was more caustic.

Third - XY-5 (solder rosin), ordered .

Like the second option, it comes in a jar, though not metal, but plastic.


Due to the solid state, it can be perfectly transported and constantly stored even in your pocket. Nothing will leak out, nothing will get dirty.

In the solid state, there is a rich amber color familiar to everyone who has worked with rosin. During heating, it melts with copious emission of smoke, which has the smell of resin, which is not surprising :) To be honest, my favorite option. Heated, it spreads well, but it also cools down quite quickly. Crumbles when solid.

Description (Google translation):
Name: Solid rosin;
Weight: 22 grams (including box).

Ascetic, but what we have, we have :)

Perhaps it is not entirely correct to compare the first two samples with this one, but, by and large, the first, second, and third are flux and are used for the same purposes.

So, let's begin.

The first wire was soldered using #2 PPD PD-18 flux. Due to the abundance of pollution and the rather large cross-section of the wire, the solder had to be used not so little: (But the result was not long in coming - the wire was soldered:


Without the use of flux, the solder on the bracket refused to stick at all. If you look at the photo above, you will see how it flowed from her, spreading over the plastic.

The second wire was soldered using hard flux No. 3 XY-5 (or rosin). To be honest, the first attempt was not entirely successful: the wire fell off the connector bracket along with all the solder :) But you can see how all the dirt gathered on the solder, and a place appeared on the bracket without pollution:


But on the second attempt, he still took his place where it was required.

Flux #1 RMA 223 was used last.


Hedgehog hedgehog, but the most important thing that is required from the flux is the hardening of the joint during soldering. So the simplest thing that came to my mind to check the results is to try to tear off the soldered wires :) Result:


As you can see, flux No. 2 worked perfectly: the solder itself remained in place, and the wire simply broke it. True, I had to pull with a fair amount of effort. Flux No. 3 (rosin) also turned out to be quite good: no matter how I pulled, the wire remained in place. The only thing that we managed to separate was the insulation from the cores :) But flux No. 1 failed. The solder just fell off and I didn’t have to strain too much for this :(

Conclusion: RMA 223 is not worth taking, it does not cope with its task as a flux (because it is more vaseline, and not a flux as such). But the XY-5 and PD-18 showed themselves on the positive side. Choosing between them, I would prefer solid flux only because it is more practical to store it, and its smell is much more pleasant :) But everyone decides for himself what to buy.

Yes, to improve the results, it would be possible to tin the wires and treat the bracket with phosphoric acid, but I wanted to know which of the fluxes would perform better in the harshest conditions :)

On this, perhaps, everything. Thank you for your attention and your time.

I plan to buy +31 Add to favourites Liked the review +49 +86

And so you decided to plunge into electronics with your head, stocked up with a soldering iron, bought solder and ... And what's next? If the worst is poor, then everyone represents how to solder, but the subtleties of the technology are far from known to many and come with experience. Well, I will speed up this disastrous process and tell you a couple of tricks.

So, you probably already read about a, so we will dance from him. In addition to a soldering iron, you will need solder and flux. More about them.

Solder.
This is a special alloy that melts at a temperature of about 200 degrees. The most common is 60/40 Alloy, aka POS-61. An alloy containing 60% tin and 40% lead. Its melting point is 183-230 degrees. Usually sold in the form of wire wound on spools.
For small installations, it is better to take the one where the diameter of the wire is smaller - it is easier to dose. I have two coils, one with 0.3mm solder wire, the other 0.6mm. Well, there is still one and a half millimeters, but I hardly use it. Only if I massively solder massive parts, where a lot of solder is needed.
It is better to buy imported solder, unfortunately the Russian product sucks all the time. Maybe there is a quality one, but usually I came across low-grade slag. A solder coil, as in the picture, should cost from 150-200 rubles, more expensive is possible, cheaper is not desirable. It is better to spend money once, but then have a beautiful and high-quality soldering and not take a steam bath. And the coil usually lasts for a year and a half or two, which is at least.
It is also useful to buy yourself some Rosé alloy. This is also like solder, but its melting point is completely ridiculous - somewhere in the region of 90-100 degrees. This alloy is sometimes useful when dismantling, but there will be a separate article on this later.

Fluxes
In the process of soldering, from heating, the parts are oxidized and the solder ceases to wet them. To prevent this from happening, fluxes are used - substances that dissolve the oxide film, contribute to soldering. By the way, if someone is not in the know, the process of coating one metal with another is called tinning. I say banal things? Well, after all, educational program is educational program! :)

Rosin

The simplest and most popular flux. It's just pure pine resin. When soldering, they first take a little solder on the tip, then they poke it into rosin to collect resin on the tip, and then quickly, until the resin has evaporated, they solder. The method is not very convenient, so they often do it differently. They take ordinary ethyl (medical) alcohol and dissolve crushed rosin in it until it dissolves. After this solution is applied with a brush to the parts to be soldered and soldered. The activity of rosin is not high, so sometimes nothing happens - the details are not tinned, but rosin has one huge advantage, which sometimes covers all its shortcomings. Rosin is completely passive. That is, it does not need to be removed from the place of soldering, since it does not oxidize or reduce metals, while being an excellent dielectric. That is why I try to make the most responsible solderings with alcohol-rosin flux.

One of my favorite fluxes. It is a red liquid, it contains rosin and a number of additives. Solder them as well as the usual alcohol-rosin flux - smear with a brush on the parts and solder. But there is one trick. In the original version, the liquid infection is smeared with a thin layer and dries instantly, in general, it is not very convenient to use it. I figured out how to overcome it.
I made myself a palette of fluxes - I pasted a bunch of caps from bottles on a small company, poured various fluxes into them and pasted this case onto a spool of solder. It turned out very convenient and compact. So, pouring into the lid, I let it stand for a couple of days. During this time, it will dry out and thicken to the state of liquid honey. Now it is already convenient to spread it with a sharp toothpick exactly where you need it. And if it thickens beyond measure, then either I’ll drop a little alcohol there, or add a little more fresh flux and stir it. The manufacturer claims that it is not necessary to rinse. In principle, it seems to be the way it is, it is not active. But something confuses me with the additives that are in it, so I always wash it off. It is washed off with a wide brush dipped in alcohol. Or just brush under running tap water. There is nothing wrong with washing the finished board with water, the main thing is to dry it well afterwards.

Rosin gel
Great stuff. Not so long ago appeared in the radio stores and has already earned my love and respect. It is a thick brown rosin-based paste, sold in syringes. It is excellently smeared directly where it is needed, does not leave carbon deposits on the soldering iron, like LTI-120. Easily washed off with water or alcohol, in general, rulez!

Killer active flux, which is easily washed off with water, does not leave dirty sticky marks and oxides. But it must be washed off. Rinse thoroughly. Otherwise, in a couple of years, it can corrode the tracks of the board or its remains will become conductive and there will be terrible leaks on the surface of the board between the tracks, which will have an extremely negative effect on the operation of the circuit. I'm also not sure about the safety of his fumes. You can use it for two times, but constantly using it somehow does not smile at me. But in general, this is an awesome flux, soldering them is a pleasure.

Glycerin-Salicylic Flux.
He's FSGL. Honestly, I have no idea where this crap comes from. I have had a bank of this flux since childhood (which is why I practically never soldered rosin) - dad stole it from a defense enterprise. I have never seen it for free sale. Solders as vigorously as Glycerin-hydrazine, but does not contain impurities that are questionable from the point of view of toxicity. It's 90% glycerin, 5% salicylic acid, 5% water. Buy chtol in the pharmacy salicylic acid and save yourself? Pretty crazy recipe. One drawback - you need to wash it off, it is active. But it washes off easily with water.

F-34A
Hellish acid mix. When soldering, it has a terrible caustic exhaust, with which I poisoned half of our laboratory. You can solder this muck only in a gas mask and with a powerful hood, but this shit solders everything that other fluxes never dreamed of even in a nightmare. This slurry tins in flight - rust, oxides, steel, coatings, even aluminum can be soldered. So if you need to solder to a rusty nail, drop that shit, hold your breath, and LUDI!

Imported non-cleaning fluxes.
To be honest, I haven't used them. They say they are cool, but IMHO it’s not rational to solder them just like that - they are too expensive, and they don’t sell them in our city, but I’m sick of ordering. Rather, they are for professional use, such as repairing cellular or soldering BGA cases (this is when the legs are in the form of an array of balls under the microcircuit case). If you are interested, then look for information on the forums of cell repairers, they know everything about this matter.

Hemp Dutch Flux
I have no idea who makes it and where they sell it, but I know for sure that it is! I was especially convinced of this after picking the product diagrams of the company where I used to work. The developers are obviously soldering them. Since I have not yet seen such stoned circuit solutions.

Soldering iron in hand and go!!!
I told you about fluxes, now, in fact, about the soldering process.
This is not a tricky thing. To begin with, it is desirable to irradiate the details. Wet them with flux, pick up a little bit of solder with a soldering iron tip and smear it over the surface. There is no need to hurry, the details should be covered with an even thin shiny layer. The conclusions of microcircuits and radio components do not need to be tinned - they are already tinned at the factory.

Solder should be liquid, like water. If it is lumpy, with pronounced graininess and matte, then there are two reasons - soldering iron temperature incorrect, or solder base shit. If the soldering iron is too cold, then the solder will be on the verge of a solid and liquid state, it will be viscous and will not wet. If the soldering iron is overheated, then the solder will instantly be covered with a gray film of oxide and will also be disgusting to tin. The ideal temperature of the soldering iron when soldering with solder POS-40 ( 60/40 Alloy), in my opinion, this is about 240-300 degrees. At ST-96 it is enough to set the regulator to 2/3 in the direction of increase.

If you solder a printed circuit board, then the tracks also need to be tinned. But this must be done carefully. Textolite, which is sold in the expanses of the Motherland, often also turns out to be rare shit, and when heated, the foil falls off from it at the moment. Therefore, it is impossible to heat the board for a long time - the tracks will fall off. Usually I just smear all the tracks well with flux and quickly run a flat tip of a soldering iron with a drop of solder over each track. As a result, I have perfectly tinned tracks, with an almost mirror-like surface.

There is a folk way for quickly tinning large boards:

A braid is taken to remove solder, this is such a copper washcloth, it is sold in coils of 30 rubles per meter. If you can't find it, you can pick out a shield braid from a thick television coaxial cable - the same garbage, only fuss more. The board is properly lubricated with flux, the braid is properly impregnated with solder and also watered with flux. Further, this crap is being soldered on the surface of the board with a soldering iron. So that the fibers of the braid do not stick to the tracks, it is better to take a larger and more massive soldering iron.

I have perfected the method.
I took an old powerful 60W soldering iron, wrapped the tip with this braid, impregnated it with Rose alloy and now a puddle of the board in one motion. Why Rose? And it’s easier for them to tinker, the soldering iron cools down sharply when it touches the board. gives off heat. If the braid is moistened with ordinary solder, then it is immediately welded to the board with separate fibers, and the Rosé alloy is light-melting and does not stick.

Soldering transistors, diodes and microcircuits.
Here I would like to draw special attention. The point is that semiconductors destroyed by too high a temperature, so there is a risk of overheating the chip. To prevent this from happening, it is advisable to set the soldering iron 230 degrees or so. This is quite a tolerable temperature, which the chip can withstand for quite a long time. You can solder and take your time. For conventional, non-adjustable soldering irons, the tip temperature is about 350-400 degrees, so you need to solder quickly, with one touch. No longer than a second on each leg and take at least a 10-15 second break before proceeding to solder the other leg. You can also hold the leg with metal tweezers - it will serve as a heat sink.

Soldering wires
It is better to service the ends separately before soldering, and if the wire is soldered to the printed circuit board, then it is very desirable to drill a hole in the board, bring it in from the other side and only then solder. In this case, the risk of tearing off the droshky when jerking the wire is reduced to zero.

Soldering with solder wire.
This is how microcircuits are usually soldered. They grab it diagonally by the extreme legs, lubricate everything with flux, and then, holding a soldering iron with one hand and a thin wire of solder with the other, quickly solder all the legs.

Soldering wires in varnish insulation
Any winding wire, such as those with which the transformer is wound, is covered with a thin layer of varnish. To solder to it, this layer of varnish must be torn off. How to do it? If the wire is thick, then you can burn it a little with the fire of a lighter, the varnish will burn, and the soot can be cleaned off with a rough cardboard. If the wire is thin, then either gently scrape it with a scalpel, holding the scalpel strictly perpendicular to the wire, or take an aspirin tablet and press and shove the hot tip of the soldering iron over the wire on the aspirin. When heated, aspirin will release a substance that will gobble up the varnish insulation and clean the wire. The truth will stink a lot :)

third hand

I recommend getting one like this. Damn handy thing, allows you to hold some Cthulhu while soldering, the ends do not hang from side to side. By the way, beware of spring-loaded conductors! When soldering, it can jump off and throw a drop of solder in your face, how many times this has already flown into my face and I don’t remember, but it could have been in the eye! So follow the safety precautions!

Sponge
The tip of the soldering iron is gradually fouled and covered with soot. This is normal, usually the flux is to blame, the same LTI-120 burns, God forbid. To clean the soldering iron, you can use a special sponge. Such a yellow garbage, comes complete with soldering iron stands. It must be moistened with water and squeezed out, leaving it damp. By the way, the sponge constantly dries up, so that it does not get wet every time, it can be soaked with ordinary medical glycerin. Then it won't dry out at all! Damn convenient! If there is no sponge, then take a cotton cloth, put it in an iron tray and also soak it with water or glycerin. Our installers kept an ordinary waffle towel on the table and wiped the soldering iron on it.

By the way, about safety.

• First, arrange everything so that it is convenient.
• Watch your power cords. soldering iron very likes to burn his own wire. He's got mania. And this is fraught at best with a wire repair, at worst with a short circuit and fire.
• Do not leave the soldering iron on even for a short time. Rule " Gone - turned off"must be done ironically.
• Rule two - the soldering iron should be either in hand or on its reliable stand. And nothing else! In no case should you put it on the table or on the first thing that popped on the table. The cord will drag him along in a moment.
• Don't forget about exhaust and ventilation. If you are soldering, then at least open the window, ventilate the room, or better, put a fan on the table (at least 80mm from the computer) or a hood.

It is better to see once than to read a hundred times:
No problems! At your service a bunch of videos from You Tube for the query "solder". See how the professionals do it. Watch and learn!

The most important element in the repair of any equipment is soldering. Solder, fluxes, solder paste - all this must be taken into account when performing repair work. If everything is relatively clear with solder - usually tin-lead solders are used for this with different ones (depending on the composition of the alloy), then what about the flux? What is it for?

The main purpose of the flux is to remove oxides from the surface, as well as to reduce surface tension in order to improve solder spreading. In addition, the flux for soldering serves to protect the joint from the effects of the external environment.

What are fluxes

According to their effect on metal surfaces, fluxes are of the following types.

In addition, for soldering products made of cast iron, carbon steels, as well as copper and its alloys, borax is used, which is a white crystalline powder with a melting point of 741 ° C.

Also, borax (more precisely, its mixture with boric acid in a ratio of 1: 1) is used for soldering stainless steel and hard

As a flux for brass products, a mixture consisting of equal parts of common salt and calcium chloride is used.

Soldering aluminum products requires a flux that has a low melting point. Flux usually contains 30 to 50% potassium chloride.

Soldering flux can be in powder, liquid, or paste form. In addition, there are special solder pastes in which the solder particles are already contained with the flux.

What is important to know when soldering

When choosing a flux for soldering, not only the material of the parts to be soldered is taken into account, but also what kind of solder is used. The melting point of the flux must not exceed the melting point of the solder.

Regardless of the type of flux used, the place to be soldered after completion of work must be wiped with a cloth soaked in acetone or rectified alcohol. Then clean this place with a brush or brush moistened with any solvent to remove flux residues. This is especially true of the active flux, since the products of its decomposition not only pollute the place of soldering, but are also a source of corrosion.